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Author Muheim, R.; Phillips, J.B.; Akesson, S. url  doi
openurl 
  Title (up) Polarized light cues underlie compass calibration in migratory songbirds Type Journal Article
  Year 2006 Publication Science (New York, N.Y.) Abbreviated Journal Science  
  Volume 313 Issue 5788 Pages 837-839  
  Keywords Alaska; *Animal Migration; Animals; Calibration; Cues; *Flight, Animal; Geography; *Light; Magnetics; *Orientation; Seasons; Sparrows/*physiology; Sunlight  
  Abstract Migratory songbirds use the geomagnetic field, stars, the Sun, and polarized light patterns to determine their migratory direction. To prevent navigational errors, it is necessary to calibrate all of these compass systems to a common reference. We show that migratory Savannah sparrows use polarized light cues from the region of sky near the horizon to recalibrate the magnetic compass at both sunrise and sunset. We suggest that skylight polarization patterns are used to derive an absolute (i.e., geographic) directional system that provides the primary calibration reference for all of the compasses of migratory songbirds.  
  Address Department of Animal Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden. rmuheim@vt.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0036-8075 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16902138 Approved no  
  Call Number IDA @ john @ Serial 243  
Permanent link to this record
 

 
Author Cao, C.; Zong, Y.; Bai, Y.; Shao, X. url  doi
openurl 
  Title (up) Preliminary study for improving the VIIRS DNB low light calibration accuracy with ground based active light source Type Journal Article
  Year 2015 Publication Proc. SPIE 9607, Earth Observing Systems XX, 2015 Abbreviated Journal  
  Volume Issue Pages 96070D  
  Keywords Remote sensing; Suomi NPP; VIIRS DNB; calibration  
  Abstract There is a growing interest in the science and user community in the Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) low light detection capabilities at night for quantitative applications such as airglow, geophysical retrievals under lunar illumination, light power estimation, search and rescue, energy use, urban expansion and other human activities. Given the growing interest in the use of the DNB data, a pressing need arises for improving the calibration stability and absolute accuracy of the DNB at low radiances. Currently the low light calibration accuracy was estimated at a moderate 15%-100% while the long-term stability has yet to be characterized. This study investigates selected existing night light point sources from Suomi NPP DNB observations and evaluates the feasibility of SI traceable nightlight source at radiance levels near 3 nW·cm−2·sr−1, that potentially can be installed at selected sites for VIIRS DNB calibration/validation. The illumination geometry, surrounding environment, as well as atmospheric effects are also discussed. The uncertainties of the ground based light source are estimated. This study will contribute to the understanding of how the Earth’s atmosphere and surface variability contribute to the stability of the DNB measured radiances, and how to separate them from instrument calibration stability. It presents the need for SI traceable active light sources to monitor the calibration stability, radiometric and geolocation accuracy, and point spread functions of the DNB. Finally, it is also hoped to address whether or not active light sources can be used for detecting environmental changes, such as aerosols.  
  Address NESDIS/STAR, National Oceanic and Atmospheric Administration, USA  
  Corporate Author Thesis  
  Publisher SPIE Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 1261  
Permanent link to this record
 

 
Author Fulbright, J.P.; Xiong, X. url  doi
openurl 
  Title (up) Suomi-NPP VIIRS day/night band calibration with stars Type Journal Article
  Year 2015 Publication Proc. SPIE 9607, Earth Observing Systems XX, 2015 Abbreviated Journal  
  Volume Issue Pages 96071S  
  Keywords Remote Sensing; Suomi NPP; VIIRS DNB; calibration  
  Abstract Observations of stars can be used to calibrate the radiometric performance of the Day/Night Band (DNB) of the Suomi-NPP instrument VIIRS. Bright stars are normally visible in the Space View window. In this paper, we describe several potential applications of stellar observations with preliminary results for several. These applications include routine trending of the gain of the highand mid-gain stages of the DNB and trending the gain ratio between those stages. Many of the stars observed by the VIIRS DNB have absolute flux curves available, allowing for an absolute calibration. Additionally, stars are visible during scheduled lunar roll observations. The electronic sector rotations applied during the scheduled lunar observations greatly increases the sky area recorded for a brief period, increasing the observing opportunities. Additionally, the DNB recorded data during the spacecraft pitch maneuver. This means the deep sky was viewed through the full Earth View. In this situation, thousands of stars (and the planet Mars) are recorded over a very short time period and over all aggregation zones. A possible application would be to create a gain curve by comparing the instrument response to the known apparent stellar brightness for a large number of stars of similar spectral shape. Finally, the DNB is especially affected the mirror degradation afflicting VIIRS. The degradation has shifted peak of the relative spectral response (RSR) of the DNB the blue and the effective band pass has been slightly reduced. The change in response for hot stars (effective temperatures of over 30,000 K) due to this degradation will differ by about 10 percent from the response change of cool stars (below 3500 K).  
  Address Science Systems and Applications, Inc., USA  
  Corporate Author Thesis  
  Publisher SPIE Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 1260  
Permanent link to this record
 

 
Author Kyba, C.C.M.; Tong, K.P.; Bennie, J.; Birriel, I.; Birriel, J.J.; Cool, A.; Danielsen, A.; Davies, T.W.; Outer, P.N. den; Edwards, W.; Ehlert, R.; Falchi, F.; Fischer, J.; Giacomelli, A.; Giubbilini, F.; Haaima, M.; Hesse, C.; Heygster, G.; Hölker, F.; Inger, R.; Jensen, L.J.; Kuechly, H.U.; Kuehn, J.; Langill, P.; Lolkema, D.E.; Nagy, M.; Nievas, M.; Ochi, N.; Popow, E.; Posch, T.; Puschnig, J.; Ruhtz, T.; Schmidt, W.; Schwarz, R.; Schwope, A.; Spoelstra, H.; Tekatch, A.; Trueblood, M.; Walker, C.E.; Weber, M.; Welch, D.L.; Zamorano, J.; Gaston, K.J. url  doi
openurl 
  Title (up) Worldwide variations in artificial skyglow Type Journal Article
  Year 2015 Publication Scientific Reports Abbreviated Journal Sci. Rep.  
  Volume 5 Issue Pages 8409  
  Keywords Skyglow; light pollution; measurements; remote sensing; sky brightness; calibration  
  Abstract Despite constituting a widespread and significant environmental change, understanding of artificial nighttime skyglow is extremely limited. Until now, published monitoring studies have been local or regional in scope, and typically of short duration. In this first major international compilation of monitoring data we answer several key questions about skyglow properties. Skyglow is observed to vary over four orders of magnitude, a range hundreds of times larger than was the case before artificial light. Nearly all of the study sites were polluted by artificial light. A non-linear relationship is observed between the sky brightness on clear and overcast nights, with a change in behavior near the rural to urban landuse transition. Overcast skies ranged from a third darker to almost 18 times brighter than clear. Clear sky radiances estimated by the World Atlas of Artificial Night Sky Brightness were found to be overestimated by ~25%; our dataset will play an important role in the calibration and ground truthing of future skyglow models. Most of the brightly lit sites darkened as the night progressed, typically by ~5% per hour. The great variation in skyglow radiance observed from site-to-site and with changing meteorological conditions underlines the need for a long-term international monitoring program.  
  Address Leibniz-Institute for Freshwater Ecology and Inland Fisheries, Berlin, Germany  
  Corporate Author Thesis  
  Publisher Nature Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2045-2322 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 1103  
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